Thank you for all your comments and remarks. It gives me a good view on what others see, and what I need to think about.
You are absolutetly right; this is kind of a sketch, and not concidered as a complete game. This is our first attempt on creating a game.
I will look into all the things you say.
At this time I will only comment the "vertical bars". They are ladders :-D.
Those are meant to be the workaround, if you are in short of available jumps, and sometimes the ladders are necessary too.
(But I didn't manage to make the "character" walk upwards in them, so I had to make tham as a "rocket-lift" instead :-D :-D :-D )